hydraulic valve adjustment - Hot Rod Forum : Hotrodders Bulletin Board
Hotrodders.com -- Hot Rod Forum



Register FAQ Search Today's Posts Unanswered Posts Auto Escrow Insurance Auto Loans
Hot Rod Forum : Hotrodders Bulletin Board > Tech Help> Hotrodding Basics
User Name
Password
lost password?   |   register now

Reply
 
LinkBack Thread Tools
  #1 (permalink)  
Old 01-06-2012, 04:30 PM
Registered User
 
Last photo:
Join Date: May 2006
Location: Napa , Ca.
Posts: 296
Wiki Edits: 0

Thanks: 0
Thanked 2 Times in 2 Posts
hydraulic valve adjustment

I just finished installing a new GM 290 hp 350 in my 57 Chevy pickup. I got it running and broke in the cam as per instructions, set the timing and and drove it around the block a few times. I want to check the valve adjustment and the paper work and spec sheets I got with the motor says zero lash + 1/8 of a turn more, this seems odd to me. Everything iv'e seen before says 1 full turn , I usually go a 1/2 turn on engines iv'e had before. Spec sheet says 1/8, should I stay at that or go a 1/4 to a 1/2 turn preload ?
Also the spec sheet says HEI distributor with 10 degrees initial advance with a total of 32 degrees at 3000 rpm and no vacuum advance just mechanical ????? What do you guys think ?
Gene
Attached Thumbnails
Click image for larger version

Name:	Misc pics 002.JPG
Views:	132
Size:	61.9 KB
ID:	61506  

    Advertisement
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
  #2 (permalink)  
Old 01-06-2012, 04:39 PM
eloc431962's Avatar
Evil Wicked Mean And Nasty
 
Last wiki edit: Pilot bearing and bushings
Last journal entry: roof repair
Last photo:
Join Date: Nov 2008
Location: back in the garage.
Posts: 13,762
Wiki Edits: 37

Thanks: 50
Thanked 28 Times in 24 Posts
I alway's go 1/4 to 1/2 myself alway's seemed to work well for me.
As far as the timing goes is that where you set it at and if so how did it do ?
You can alway's tweak around with the timing till it hits the sweet spot for you. JMO



Cole
Reply With Quote Quick reply to this message
  #3 (permalink)  
Old 01-06-2012, 05:35 PM
cobalt327's Avatar
WFO
 
Last wiki edit: Intake manifold
Last journal entry: 1980 Malibu Wagon
Last photo:
Join Date: Mar 2009
Location: Atlanta
Age: 59
Posts: 5,037
Wiki Edits: 1616

Thanks: 128
Thanked 597 Times in 546 Posts
Quote:
Originally Posted by 57halfton
I just finished installing a new GM 290 hp 350 in my 57 Chevy pickup. I got it running and broke in the cam as per instructions, set the timing and and drove it around the block a few times. I want to check the valve adjustment and the paper work and spec sheets I got with the motor says zero lash + 1/8 of a turn more, this seems odd to me. Everything iv'e seen before says 1 full turn , I usually go a 1/2 turn on engines iv'e had before. Spec sheet says 1/8, should I stay at that or go a 1/4 to a 1/2 turn preload ?
Also the spec sheet says HEI distributor with 10 degrees initial advance with a total of 32 degrees at 3000 rpm and no vacuum advance just mechanical ????? What do you guys think ?
Gene
Use the factory recommendations on the lifter preload. The ignition timing recommendations are out to lunch.

A thread that may help- No vacuum advance needed?
Reply With Quote Quick reply to this message
  #4 (permalink)  
Old 01-06-2012, 06:02 PM
Custom10's Avatar
my KARMA ran over my DOGMA
 

Last journal entry: SS
Last photo:
Join Date: May 2009
Location: Saskatchewan, Canada
Age: 49
Posts: 1,096
Wiki Edits: 0

Thanks: 15
Thanked 26 Times in 23 Posts
As far as rockers 1/2 turn is a good place for them works for me anyhow. GM most likely does not want anyone to over do it and break something so they go easy on the adjustment turns.

From what I know, GM Cam on that 290HP is too aggressive, it is over cammed. I would adjust timing at (no vac adv) 4000 rpm and set it at 36 deg total, then let it idle. Adjust the carb idle and mixture with vacuum gage, set rpm and check the timing, take a reading. It should be no lower than 14, I think 10 is too low for that 350.

If the base timing is 14 16 18 20 so be it, your done with mechanical timing and base timing other than the springs for the rate.

If you cant get the base timing over 14 without exceeding 36 Deg total BTDC @ 4000 rpm, then limit the mechanical advance

Is this the HEI dist that came with the 350? Curious to know all about the amount of mech and vacuum advance it came with.

Add your vacuum advance on manifold vac and take a timing reading at idle. Adjust idle for RPM. Adding vacuum advance at idle will help that cam/engine run better.

Figure out what that vac adv is adding, if the total, total base+mech+vac adv is over 50 deg BTDC you need to limit the vacuum advance.
Reply With Quote Quick reply to this message
  #5 (permalink)  
Old 01-06-2012, 06:04 PM
eloc431962's Avatar
Evil Wicked Mean And Nasty
 
Last wiki edit: Pilot bearing and bushings
Last journal entry: roof repair
Last photo:
Join Date: Nov 2008
Location: back in the garage.
Posts: 13,762
Wiki Edits: 37

Thanks: 50
Thanked 28 Times in 24 Posts
Mark is correct about the factory settings i would run it like that for awhile then make some changes later or when you feel they are needed. JMO
I usually do actually start out with 1/8 but i usually end up with at least 1/4 to 1/2 before it's done. IMHO



Cole
Reply With Quote Quick reply to this message
  #6 (permalink)  
Old 01-06-2012, 06:06 PM
eloc431962's Avatar
Evil Wicked Mean And Nasty
 
Last wiki edit: Pilot bearing and bushings
Last journal entry: roof repair
Last photo:
Join Date: Nov 2008
Location: back in the garage.
Posts: 13,762
Wiki Edits: 37

Thanks: 50
Thanked 28 Times in 24 Posts
Quote:
Originally Posted by Custom10
As far as rockers 1/2 turn is a good place for them works for me anyhow. GM most likely does not want anyone to over do it and break something so they go easy on the adjustment turns.

From what I know, GM Cam on that 290HP is too aggressive, it is over cammed. I would adjust timing at (no vac adv) 4000 rpm and set it at 36 deg total, then let it idle. Adjust the carb idle and mixture with vacuum gage, set rpm and check the timing, take a reading. It should be no lower than 14, I think 10 is too low for that 350.

If the base timing is 14 16 18 20 so be it, your done with mechanical timing and base timing other than the springs for the rate.

If you cant get the base timing over 14 without exceeding 36 Deg total BTDC @ 4000 rpm, then limit the mechanical advance

Is this the HEI dist that came with the 350? Curious to know all about the amount of mech and vacuum advance it came with.

Add your vacuum advance on manifold vac and take a timing reading at idle. Adding vacuum advance at idle will help that cam/engine run better.

Figure out what that vac adv is adding, if the total, total base+mech+vac adv is over 50 deg BTDC you need to limit the vacuum advance.
^^^^Good point.



Cole
Reply With Quote Quick reply to this message
  #7 (permalink)  
Old 01-06-2012, 11:58 PM
cobalt327's Avatar
WFO
 
Last wiki edit: Intake manifold
Last journal entry: 1980 Malibu Wagon
Last photo:
Join Date: Mar 2009
Location: Atlanta
Age: 59
Posts: 5,037
Wiki Edits: 1616

Thanks: 128
Thanked 597 Times in 546 Posts
Quote:
Originally Posted by eloc431962
Mark is correct about the factory settings i would run it like that for awhile then make some changes later or when you feel they are needed. JMO
I usually do actually start out with 1/8 but i usually end up with at least 1/4 to 1/2 before it's done. IMHO



Cole
My thoughts on why they say to nearly "zero lash" that particular engine/cam combo has to do w/using that cam w/basically stock springs. The weak springs can allow the lifters to pump up and if there's enough preload this pump up effect will severely limit RPM and power. The factory lifters don't have the internal C-clip pushrod cup retainers, so they shouldn't be actually zero lashed, hence they say to use the minimum amount of preload that will keep the p-rod cup/piston from hitting the retainer clip.

There are vendors like Pace Performance who say that 34 degrees total timing should be used- much closer to what that engine actually needs, IMO. Giving it enough initial timing (14-16 degrees or thereabouts) along w/a vacuum advance supplying about 10-12 degrees timing at light throttle cruise will give you an engine that will be much better to drive and get better mileage to boot.
Reply With Quote Quick reply to this message
  #8 (permalink)  
Old 01-07-2012, 11:05 AM
Registered User
 
Last photo:
Join Date: May 2006
Location: Napa , Ca.
Posts: 296
Wiki Edits: 0

Thanks: 0
Thanked 2 Times in 2 Posts
Well it seems that after reading other posts that my engine choice wasn't a good one. I am going to adjust my valves as recommended without the engine running then move on to the timing. Is there anything I can do with the distributor to wake this turd up some ? Did I post this thread in the wrong place ? Why was it moved ?
Gene
Reply With Quote Quick reply to this message
  #9 (permalink)  
Old 01-07-2012, 11:47 AM
techinspector1's Avatar
Senior Curmudgeon
 
Last wiki edit: DynoSim combinations Last photo:
Join Date: Oct 2005
Location: Hemet, California, USA
Age: 72
Posts: 12,946
Wiki Edits: 326

Thanks: 760
Thanked 1,009 Times in 848 Posts
Quote:
Originally Posted by cobalt327
My thoughts on why they say to nearly "zero lash" that particular engine/cam combo has to do w/using that cam w/basically stock springs. The weak springs can allow the lifters to pump up and if there's enough preload this pump up effect will severely limit RPM and power. The factory lifters don't have the internal C-clip pushrod cup retainers, so they shouldn't be actually zero lashed, hence they say to use the minimum amount of preload that will keep the p-rod cup/piston from hitting the retainer clip.

There are vendors like Pace Performance who say that 34 degrees total timing should be used- much closer to what that engine actually needs, IMO. Giving it enough initial timing (14-16 degrees or thereabouts) along w/a vacuum advance supplying about 10-12 degrees timing at light throttle cruise will give you an engine that will be much better to drive and get better mileage to boot.
Excellent info Mark, thanks.
Richard
Reply With Quote Quick reply to this message
  #10 (permalink)  
Old 01-07-2012, 03:00 PM
eloc431962's Avatar
Evil Wicked Mean And Nasty
 
Last wiki edit: Pilot bearing and bushings
Last journal entry: roof repair
Last photo:
Join Date: Nov 2008
Location: back in the garage.
Posts: 13,762
Wiki Edits: 37

Thanks: 50
Thanked 28 Times in 24 Posts
Quote:
Originally Posted by techinspector1
Excellent info Mark, thanks.
Richard
Yes it is Richard.




Cole
Reply With Quote Quick reply to this message
  #11 (permalink)  
Old 01-07-2012, 04:37 PM
Registered User
 
Last photo:
Join Date: May 2006
Location: Napa , Ca.
Posts: 296
Wiki Edits: 0

Thanks: 0
Thanked 2 Times in 2 Posts
In another thread it seems that the thinking is that the cam is to big for the compression ratio, to much duration for 8 1/2 to 1 comp. The cam that is in it is .450 / .460 lift and 222 /222 duration @ .050 lift. The heads are 76 cc chambers w/ 1.94 intakes and 1.50 exhausts. My pickup weights about 3250 lbs. with a 350 turbo trans w/ stock converter and a 3.08 rear gear. I just want it to be a good driver for around town and out on the hiway.
So now i'm thinking a cam change may be the thing to do, something with less duration and maybe more vacuum.
What do you guys think ?????
Gene
Reply With Quote Quick reply to this message
  #12 (permalink)  
Old 01-07-2012, 09:37 PM
cobalt327's Avatar
WFO
 
Last wiki edit: Intake manifold
Last journal entry: 1980 Malibu Wagon
Last photo:
Join Date: Mar 2009
Location: Atlanta
Age: 59
Posts: 5,037
Wiki Edits: 1616

Thanks: 128
Thanked 597 Times in 546 Posts
Quote:
Originally Posted by 57halfton
In another thread it seems that the thinking is that the cam is to big for the compression ratio, to much duration for 8 1/2 to 1 comp. The cam that is in it is .450 / .460 lift and 222 /222 duration @ .050 lift. The heads are 76 cc chambers w/ 1.94 intakes and 1.50 exhausts. My pickup weights about 3250 lbs. with a 350 turbo trans w/ stock converter and a 3.08 rear gear. I just want it to be a good driver for around town and out on the hiway.
So now i'm thinking a cam change may be the thing to do, something with less duration and maybe more vacuum.
What do you guys think ?????
Gene
Seems you have two threads dealing w/the cam now. Hopefully the replies won't start to get too confused being posted in two places.

Anyway, Techinspector1 has compiled a Wiki page on cam to CR compatibility, located HERE.

We see that a cam having 222 degrees duration @ 0.050" lift is better used on an engine having about 10:1 static CR. We can also see an engine having 8.5:1 SCR is better served by using a cam w/ about 194 degrees duration @ 0.050" lift. There is some fudge room here, but using a 222 degree cam w/8.5:1 SCR ain't gonna make a world beater, and that's a fact.

Personally I do not make specific camshaft recommendations. I'll give you info needed so that you can make an informed decision for yourself (one of those "teach a man to fish..." kind of things), or just ask and someone here will feed you a cam that will make you happier than the cam you now have.
Reply With Quote Quick reply to this message
  #13 (permalink)  
Old 01-07-2012, 09:53 PM
Registered User
 
Last photo:
Join Date: May 2006
Location: Napa , Ca.
Posts: 296
Wiki Edits: 0

Thanks: 0
Thanked 2 Times in 2 Posts
Thanks Cobalt , I will check techinspector's wiki page. I was thinking Monday I would call some cam manufactures and talk to their tech people and see what they recommend. I read the other thread I believe you posted and was reading what Oldboogie said, thats why i'm fishing in 2 threads.
Thanks , Gene
Reply With Quote Quick reply to this message
  #14 (permalink)  
Old 01-07-2012, 10:34 PM
cobalt327's Avatar
WFO
 
Last wiki edit: Intake manifold
Last journal entry: 1980 Malibu Wagon
Last photo:
Join Date: Mar 2009
Location: Atlanta
Age: 59
Posts: 5,037
Wiki Edits: 1616

Thanks: 128
Thanked 597 Times in 546 Posts
Comp Cams has a program that you might get a kick out of using. It's HERE. Basically you input the engine and vehicle specs and it makes a recommendation based on your input.

Giving the cam company techs a call would also be a good place to start.
Reply With Quote Quick reply to this message

Recent Hotrodding Basics posts with photos

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the Hot Rod Forum : Hotrodders Bulletin Board forums, you must first register.
Please enter your desired user name (usually not your first and last name), your email address and other required details in the form below.
User Name:
If you do not want to register, fill this field only and the name will be used as user name for your post.
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.




Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools

Posting Rules
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Valve adjustment/ Hydraulic lifter? jason777 Engine 10 09-24-2011 01:28 PM
valve adjustment on a ford 302 with hydraulic cam davidgroot562 Hotrodding Basics 2 09-02-2011 06:20 AM
sbc hydraulic valve adjustment hottrodz Engine 10 12-16-2006 10:46 PM
Hydraulic valve adjustment? HotRodMan Engine 3 10-02-2006 09:49 AM
Hydraulic Valve Adjustment bandar93001 Engine 14 07-01-2004 06:02 PM


All times are GMT -6. The time now is 04:11 PM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0 PL2
Copyright Hotrodders.com 1999 - 2012. All Rights Reserved.